Articles: dexmedetomidine.
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Randomized Controlled Trial Clinical Trial
The effect of intravenous dexmedetomidine premedication on the dose requirement of propofol to induce loss of consciousness in patients receiving alfentanil.
Dexmedetomidine reduces the dose requirements for opioids and anaesthetic agents. We conducted a single-centre, open-label, noncomparative phase II study of the effect of intravenous dexmedetomidine on the dose requirement of propofol to induce loss of consciousness in 49 ASA I and II patients. ⋯ The ED50 for the final infusion rate of propofol to suppress consciousness was 3.45 mg x kg(-1) x h(-1) (95% CL 2.7-4.2): ED95 was 6.68 mg x kg(-1) x h(-1) (95% CL 5.1-19.1), EC50 was 1.69 microg x ml(-1) (95% CL 0.95-2.5) and EC95 was 5.7 microg x ml(-1) (95% CL 3.2 to > 10). Our final dose of dexmedetomidine of 0.63 microg x kg(-1) caused a reduction in the overall concentration and dose of propofol required to produce loss of consciousness, but no significant shift in the dose-response curve compared with other studies.
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J Vet Med A Physiol Pathol Clin Med · May 2001
Randomized Controlled Trial Comparative Study Clinical TrialComparison of medetomidine and dexmedetomidine as premedication in isoflurane anaesthesia for orthopaedic surgery in domestic sheep.
The objective of the present study was to determine the potency of dexmedetomidine in relation to medetomidine in sheep undergoing orthopaedic surgery by comparing the anaesthetic requirements and cardiovascular changes at a dose relationship that represented equipotency in vitro. Twenty-four non-pregnant, female sheep were used. The study was carried out as a blind, randomized, experimental trial. ⋯ Average mean PaO2 were 279.54 +/- 113.37 mmHg and 220.21 +/- 102.15 mmHg with individual minimum values of 27.2 mmHg and 58.5 mmHg in groups 1 and 2, respectively. In conclusion, intravenous dexmedetomidine at 5 micrograms/kg BW and medetomidine at 10 micrograms/kg BW have the same effects on isoflurane requirements and cardiopulmonary parameters in sheep, indicating an equipotent dose relationship. Both preparations induced moderate to severe hypoxaemia in individual sheep.
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To determine whether a high dose of levomedetomidine had any pharmacologic activity or would antagonize the sedative and analgesic effects of dexmedetomidine in dogs. ⋯ Results suggest that administration of dexmedetomidine alone may have some cardiovascular benefits over administration of medetomidine, which contains both dexmedetomidine and levomedetomidine. Further studies are needed to confirm the clinical importance of the effects of levomedetomidine in dogs.
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Randomized Controlled Trial Clinical Trial
Effect of dexmedetomidine on propofol requirements in healthy subjects.
Dexmedetomidine-propofol pharmacodynamic interaction was evaluated in nine healthy subjects in a crossover design. Dexmedetomidine/placebo was infused using a computer-controlled infusion pump (CCIP) to maintain a pseudo-steady-state plasma concentration of 0.66 +/- 0.080 or 0 ng/mL, respectively. Forty-five minutes after the dexmedetomidine/placebo infusion was started, propofol was infused using a second CCIP to achieve a stepwise logarithmically ascending propofol concentration (1.00 to 13.8 microg/mL) profile. ⋯ The apparent EC50 values of propofol (EC50APP; concentration of propofol at which the probability of achieving a pharmacodynamic endpoint is 50% in the presence of dexmedetomidine concentrations observed in the current study; dexmedetomidine treatment) were 0.273, 0.544-0.643, and 3.89 microg/mL for the ability to hold a syringe, sedation scores, and motor response, respectively. Dexmedetomidine reduced propofol concentrations required for sedation and suppression of motor response. Therefore, the propofol dose required for sedation and induction of anesthesia may have to be reduced in the presence of dexmedetomidine.